Question

Tornaria is larva of
A. Balanoglossus
B. Herdmania
C. Starfish
D. Pila

Answer 1

Hint: Tornaria is larva of some species of hemichordata such as acorn worms, which is very much similar to the bipinnaria larvae appearance of starfishes.

Complete answer:
Tornaria larva is planktonic larvae of some hemichordates. Plankton are the organisms that live in large bodies of water and are unable to swim against a current. Hemichordate are a group of wormlike marine invertebrates closely related to chordates and echinoderms and usually constitute a phylum, the Hemichordata. Tornaria is similar in appearance with larvae of starfish.

> Option A is Balanoglossus. Balanoglossus is a hemichordate and yes, its larva is called tornaria.
> Options B is herdmania. Herdmania belongs to phylum chordata. Larva of herdmania is called ascidian tadpole larva. So, this option is wrong.
> Option C is star fish. Starfish also belong to phylum Echinodermata. As we already mentioned, the larva of a starfish looks like tornaria but it is different. Larva of starfish is called bipinnaria larva. So, this is the wrong option.
> Option D is pila. Pila belongs to the phylum mollusca and is non-chordate. Larva of mollusca is called Veliger. So, this option is also wrong.

So, the correct option is A) Balanoglossus.

Additional information:
The size of tornaria larva varies from 1 mm to 3 mm. It has a ventral mouth near the equatorial plane of the body, a posterior terminal anus and gut differentiated into an esophagus, stomach and intestine. The cilia form two bands on the body surface.

Note: This is a very simple question. If we know which is chordata and which is hemichordata or non chordata, we can do this question by only reading options because in this question only one is hemichordata.